1. Field of the Invention
The present invention relates to an optical receiver module, in particular, the invention relates to an optical receiver module that receives a wavelength-multiplexed signal that multiplexes optical signals each attributed to a specific wavelength different from each other, and converts the optical signals into electrical signals.
2. Related Background Arts
As the communication capacity explosively increases, not only an accelerated transmission speed but a thicker transmission capacity has been requested. The transmission speed reaches, for instance, 40 Gbps (gig-bit per second), and sometimes exceeds 100 Gbps. The thicker transmission capacity is going to be accomplished by a wavelength division multiplexing (WDM) system where optical signals are transmitted as being multiplexed by wavelengths thereof.
A receiver optical receiver module that receives such a wavelength-multiplexed signal requires a function of de-multiplexing the wavelength-multiplexed signal and generating or recovering optical signals independent to each other. United States Patent US2013/148970A has disclosed such an optical receiver module that receives the wavelength-multiplexed signal.